DE2617425A1 - REEL CORE FOR RAIL MATERIAL - Google Patents

Description

-ρ D I / "if * patent attorneys:

I IEDTKE - DÜHLING - IVlNNE - CLRUPE

Dipl.-Ing. Tiedtke Dipl.-Chem. Bühling Dipl.-Ing. Kinne 2617425 Dipl.-Ing. Group

8000 Munich2, Postfach 202403 Bavariaring 4

Tel .: (0 89) 53 96 53 - 56

Telex: 5 24845 tipat

cable. Germaniapatent Munich

April 21, 1976

B 7306

ICI case P.27767

IMPERIAL CHEMICAL INDUSTRIES LIMITED London, United Kingdom

Winding core for web material

The invention relates to cores which are used for winding flat and sheet material of greater length, e.g. for plastic films, Fabric or paper webs can be used.

In order to facilitate storage and transportation, a web material is often wound on a core, which is usually the case is a rigid paper tube or cylinder bounded by a plurality of longitudinal, spaced-apart parallels Laths is formed. However, there is a problem with winding; even with the most carefully controlled manufacturing process a web material, in particular a web of oriented thermoplastic film, ribs or ribs running in the longitudinal direction Depressions that result from the smallest changes in thickness across the width of the web. When winding a web, the

ORIGINAL INSPECTED

261742 *

speaking ribs or elevations and depressions of adjacent layers of the web with each other, so that a plurality of superimposed, successive elevations results in the transverse direction by a plurality of superimposed depressions are separated, which are a little apart from each other. This is detrimental to web materials that are used during storage Tend to shrink. Depressions can shrink during storage because they are spaced apart and give space to the Have available shrinkage, while the elevations rest directly on one another and have no shrinkage space. It will be through it stretched the elevations relative to the depressions, resulting in longitudinally extending, distorted areas that are called "Stretching or folding strips" are known, which effectively convey the web material to fast packing machines or fast printing presses hinder.

The invention provides a core suitable for winding shrinkable web material which is axially extending dimensionally stable inner area and a resiliently compressible area has outer surface area made of layers of resiliently compressible film. made of foamed crystalline aliphatic There is polyolefin material that permanently surrounds the dimensionally stable inner area. To cores made according to the invention Wrapped, shrinkable sheet materials show a reduced tendency to form stretch marks. The resiliently compliant compressible film is made of foamed polyolefin material that preferably a density of 5 to 50 and in particular such a density of 8 to 30% of the density of the polyolefin material in unfoamed

snno / e / ftsia ORIGINAL INSPECTED

State owns. It is preferred that the foam be an open cell Foam is because there may be compression and resilience of the foam due to the entry and exit of air supported in the open cells or out of the open cells will. The preferred film thickness is 0.1 to 1 mm and in particular 0.4 to 0.7 mm, the film preferably being an air

_2

permeability of (2 to 50 and especially 15 to 30) x10 ml

2 - 1

(cm. sec.cm water column), measured according to "British Standard 2925".

Examples of useful resiliently compressible films or sheets made from foamed aliphatic polyolefin materials are described in GB-PS 1,220,053. By "aliphatic polyolefin material" is meant compositions that are a polymer contain, which consists of a major proportion of polymerized aliphatic monoolefin such as ethylene or propylene. In specific Mixtures of low-density polyethylene (i.e. density below 0.94 g / cm) with between 10 to 40% (% by weight based on the Mixture weight) of a more crystalline polyolefin such as high density polyethylene or propylene offer an attractive balance between resilience and compressibility.

The cores used for winding web material must be sufficiently dimensionally stable so that their shape in the Maintain the amount of time between their manufacture and their insertion into a rewinder. Obtained the cores according to the invention their dimensional stability through the axially extending inner area. This inner area can consist of a conventional rigid paper tube, which has the advantages of low weight, low cost and being well known in the trade; the inner area can also be a cylinder

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be, which consists of a plurality of longitudinally extending parallel slats, which are also known in the trade. The resiliently resilient! Compressible outer surface area can thereby be attached to the pipe, that a foam sheet is wound on the pipe and then the film., thereby permanently the pipe is attached by moving the edge of the extreme end of the length of foam sheet to the edge immediately below this end edge The film layer located is stuck. The foam sheet length used should preferably be so long that it is between 3 to 20 Provides layers of film on the pipe and creates a core whose radius is 1 to 5 mm longer than the radius of the pipe. The tube can alternatively be made of metal or thermoplastic material instead of paper, for example. is the core is a cylinder made of slats, these slats can be made of aluminum or wood, attached to a pair of axially spaced apart standing discs are attached. • I

c ■,

Alternatively, the core can have an axially extending, dimensionally stable inner area made of inner layers made from resiliently flexible have compressible foamed film, which has been made dimensionally stable in that it is coated or impregnated with an adhesive which dries to form a rigid structure. A water-based starch adhesive can be used for this purpose. One possible method for making this species of cores consists in winding a length of foam sheet onto a lubricated, polished metal mold core and winding it outwards facing surface of at least each of the innermost film layers coated with the adhesive, while these layers are on the mold core

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be wrapped. In this way, the outwardly facing surface of a coated sheet becomes with the inwardly facing surface the next layer glued, so that at least the innermost layers solidify when the adhesive dries and are dimensionally stable State can be lifted from the mold core.

The invention is explained in more detail below with reference to schematic drawings of several exemplary embodiments.

Fig. 1 is a side view of a cylindrical core;

Fig. 2 is a sectional view taken along line A-A in Fig. 1;

Figure 3 is an end view, on the same scale, of an alternate embodiment of a cylindrical core . ■. · Like FIG. 2;

Figure 4 is a view of another embodiment of a cylindrical core;

Fig. 5 is an end view of the embodiment of Fig. 1 on an enlarged scale.

Fig. 1 shows a cylindrical core 1 with an axially extending dimensionally stable inner area, which consists of a rigid Paper tube 2 and a resiliently compressible outer surface area 3 consists of layers 5 of a resiliently flexible

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compressible film made of an open-cell foamed mixture made of low-density polyethylene with 20% by weight high-density polyethylene is formed. The foam has open cells 4 and a density of 0.9 g / cm. The film is 0.6 mm thick and is firmly attached to the pipe by means of an axially extending adhesive strip 7 which holds the edge 6 in place.

Fig. 3 shows an alternative embodiment of a cylindrical core 1a, in which the tube is replaced by additive layers 5a made of rolled-up foamed polyethylene film is. Some of the open cells of layers 5 and 5a are filled with a starch-based adhesive which forms a rigid Structure is dried and gives the inner region of the cylindrical core 1a dimensional stability.

Referring to Figures 1, 2 and 3, a surface waving technique was used Polyprolyp film wound on cores. It was found that there was a tendency for the formation of stretch marks was noticeably decreased in polypropylene films. Also causes the surface irregularity resulting from the edge 6 has no adverse consequences for the film. This stands in considerable Contrasted with the behavior of cores made entirely of paper tubes where difficult precautions were taken must be in order to ensure that the paper tube has an absolutely smooth and uniform surface. Have paper tubes furthermore the disadvantage of shrinkage during storage, so that it is not uncommon for paper tubes to be wound out of a Existing roll of web material fall out.

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For comparison, polypropylene film was wound onto a core which was modified from that in FIGS. 1 and 2, the layers 5 made of foamed polyethylene with layers of open-cell polystyrene film been replaced. It has been found that the use of polystyrene does not eliminate the problem of stretch strips could.

Figs. 4 and 5 show an embodiment of a cylindrical Kerns that is suitable for production in a continuous process. The cylindrical core 1b is made of concentric and helically wound strips 9a and 9b made of a sheet of open-cell foamed polyethylene. The Stripes 9a and 9b are wound staggered so that terminals 10 between abutting strip edges do not have corresponding terminals 10 of the strip underneath coincide. Some of the open cells of the strips 9b are rigid with a Filled dried adhesive, which gives the strip 9b and thus the axially extending inner region of the core 1b dimensional stability. The loose ends 11 of the strips 9a are glued in place with the aid of glue (not shown).

The helically wound structure of the core 1b allows continuous production of cores by helically winding, as it is already used in the manufacture of helically wound paper tubes. Since the cores 16 continuously can be generated, they can be cut to a wide variety of lengths as required.

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$ 261,742

The invention thus provides a roll of goods made of shrinkable web material, the latter on a core as described above is wrapped. That is, the invention provides cylindrical cores for winding web materials (in particular thermoplastic films), the cores being resiliently resilient have a compressible outer surface area made up of layers a resiliently compressible foamed synthetic material. The synthetic material or plastic material is preferably a crystalline polyolefin, in particular a mixture of low-density and high-density polyethylene.

609846/0879

Claims (4)

Claims 1. Winding core for winding web material, which has axially extending inner and outer regions, the inner area is dimensionally stable and the outer area provides a surface around which sheet material can be wrapped, thereby characterized in that the outer region (3) consists of about 3 to 20 layers of resiliently resilient compressible film (5) from one foamed crystalline polyolefin material, which is fixed around the dimensionally stable inner area (2) for a long time. 2. winding core according to claim 1, characterized in that the thickness of the resilient film (5) between 0.1 to 1 mm and is preferably between 0.4 to 0.7 mm. 3. Winding core according to claim 2, characterized in that the density of the film (5) made of foamed material between up to 50% of the density of this material in the unfoamed state. 4. Winding core according to one or more of the preceding Claims, characterized in that the foamed film is an open-cell foamed film. S0984S / 0679 Blank page